The present invention relates generally to a shaft mounting assembly. More particularly, the invention relates to a multi-piece bearing subassembly securable as a single unit to a shaft within a shaft mounting assembly.
Shaft mounting assemblies are often designed to be quickly attached to a shaft. Typically, a bearing subassembly is first slipped along the shaft to the desired position. Once there, the inner ring of the bearing subassembly is secured to the shaft utilizing one of various clamping techniques, such as use of a tapered adapter having a tapered outer surface and an axial bore for receipt of the shaft. The tapered adapter is forced axially into a tapered opening in the inner ring by manipulation of an adjusting nut. The tapered adapter is closed around the shaft by mating threads on one end of the adapter and corresponding threads on the adjusting nut. Further sliding of the bearing inner ring along the tapered outer surface achieves a press fit between the tapered surfaces.
Generally, bearing subassemblies utilizing tapered adapters have been commercially available in two types, a pull type and a push type. One pull-type adapter is illustrated in U.S. Pat. No. 5,011,306 issued Apr. 30, 1991 to Martinie. In the pull type, threads are defined on the tapered adapter adjacent its lesser diameter end, and an adjusting lock nut is tightened onto the threads to pull the tapered adapter into the shaft bore of the bearing subassembly. A number of push-type adapter designs are shown in U.S. Pat. No. 5,685,650 issued Nov. 11, 1997 to Martinie et al. In a push-type adapter, threads are disposed on the greater diameter end of the adapter, and the adapter is pushed into the bearing inner ring by rotation of the adjusting nut relative to the adapter. In one of the push-type designs, a radially-compressible snap ring provides an annular interconnection between the adjusting nut and bearing inner ring. The snap ring is placed in a groove on an outer surface of the bearing inner ring and the nut is axially moved onto the bearing inner ring such that the nut leading surface compresses the snap ring into the groove. When an opposed groove in an inner surface of the nut is aligned with the groove in the bearing inner ring, the snap ring expands into the nut groove to connect the nut and inner ring member.
A limitation of this design is the occasional inability to ascertain whether the snap ring is seated properly due to burrs or other anomalies on the snap ring. Further, even if a snap ring is seated properly, large load forces could, on rare occasions, cause a defective snap ring to break or prematurely unseat. Improperly seated, broken, or unseated rings could lead to separation of the bearing assembly, potentially resulting in equipment damage and costs associated with servicing affected equipment.
OBJECTIVE AND SUMMARY OF THE INVENTION
It is accordingly an objective of the present invention to provide a bearing subassembly having a positive locking arrangement between the inner ring and adjusting nut.
It is another objective of the present invention to provide an improved shaft mounting assembly for securing a bearing to an elongated shaft.
It is yet another objective of the invention to provide a simple, economical, and reliable locking arrangement and clamping assembly.
Some of these objects are achieved by a bearing subassembly according to the present invention. The bearing subassembly includes a bearing inner ring with an axial opening. The bearing inner ring has an outer surface which includes a circumferential portion having at least one recess. An adapter extends around the shaft and within the axial opening of the bearing inner ring. An annular adjusting nut is configured to receive the bearing inner ring and to be secured to the adapter. The adjusting nut defines an internal surface and an inner groove disposed circumferentially about the adjusting nut internal surface. The adjusting nut further defines an external surface and a bore extending between the adjusting nut external surface and the adjusting nut inner groove. Securement members are insertable through the bore and disposed between the adjusting nut inner groove and the bearing inner ring recess to axially secure the bearing inner ring member to the adjusting nut. In this construction, the inner ring recesses may be bowl shaped pockets.
In another exemplary construction, an adjusting nut kit for securing a rotatable shaft to a bearing inner ring having a plurality of recesses on its outer surface to a shaft mounting assembly includes an annular adjusting nut having an internal surface defining an inner circumferential groove. The adjusting nut further defines a bore in communication with the groove. The groove in the adjusting nut opposes the recesses in the bearing inner ring member when the adjusting nut is secured to the adapter. Balls are insertable through the bore into the recesses and the groove to axially secure the adjusting nut to the bearing inner ring member. A set screw, for example, can be used to close the radial bore.
Another aspect of the invention includes a method of securing a bearing subassembly to a shaft. The method comprises sliding an inner ring with recesses disposed circumferentially on one end of the ring onto the shaft. Next, a tapered adapter is slid onto the shaft proximate the inner ring. An adjusting nut with a circumferential groove disposed internally about one end is then slid onto the shaft via the nut""s bore. The adjusting nut is mated to one end of the inner ring. The other end of the adjusting nut is mated to one end of the adapter. The adjusting nut is rotated until the bore aligns with one of the recesses so that they oppose the opposite groove. A ball bearing is inserted through the bore into the recess. The adjusting nut is rotated repeatedly and balls are inserted until the recesses are filled. The bore is closed and the adjusting nut is rotated to axially press fit the adapter to the shaft.
Other objectives, features, and aspects of the present invention are discussed in greater detail below or may be learned through practice of the invention.